JP2023138604A - transmission line - Google Patents

Abstract

To provide a transmission line which can materialize reduction of a transmission loss thereof.SOLUTION: The transmission line comprises: an element body; a signal conductor layer; and a first ground conductor layer. The element body includes a first insulator layer and a second insulator layer of a single layer. The signal conductor layer is arranged below the first insulator layer side in a vertical direction of the element body. The first ground conductor layer is arranged above the first ground conductor layer in the vertical direction of the element body from the ground conductor layer. In the first ground conductor layer, a first vacancy hole is arranged for penetrating the first ground conductor layer to the vertical direction of the element body. In the second insulation layer, a second vacancy hole for penetrating the second insulation layer to the vertical direction of the element body is arranged. At least a part of the first vacancy hole is overlapped with the signal conductor layer in view of the vertical direction of the element. A left portion of a surface where the first vacancy hole is formed includes a portion positioned in the left in a longitudinal direction from a surface where the second vacancy hole is formed in a cross section orthogonal to a cross direction of the element body.SELECTED DRAWING: Figure 2

Description

The present invention relates to a transmission line through which high frequency signals are transmitted.

As an invention related to a conventional transmission line, for example, a signal transmission line described in Patent Document 1 is known. This signal transmission line includes a laminate, a signal conductor, and a ground conductor. The laminate has a structure in which a plurality of resin layers are laminated. The signal conductor and the ground conductor overlap when viewed in the stacking direction of the laminate. Further, a hollow portion is provided between the signal conductor and the ground conductor.

In such a signal transmission line, air having a low dielectric constant exists in the hollow portion. The hollow portion is provided near the signal conductor. Therefore, the dielectric constant around the signal conductor becomes low. As a result, in the signal transmission line, the occurrence of dielectric loss in the high frequency signal transmitted through the signal conductor is suppressed, so that the transmission loss of the signal transmission line is reduced.

Patent No. 6489265

By the way, in the field of signal transmission lines described in Patent Document 1, there is a desire to further reduce transmission loss of signal transmission lines.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a transmission line that can reduce transmission loss of the transmission line.

The transmission line according to one embodiment of the present invention is
an element body having a main surface having a normal extending in the vertical direction of the element body, the element body including a single layer of a first insulator layer and a second insulator layer;
a signal conductor layer provided in the element body below the first insulator layer in the element body vertical direction;
a first ground conductor layer provided above the first insulator layer in the element body in the vertical direction of the element body;
It is equipped with
The first insulator layer is provided with a first hole that penetrates the first insulator layer in the vertical direction of the element body,
The second insulator layer is provided with a second hole that penetrates the second insulator layer in the vertical direction of the element body,
The direction in which the signal conductor layer extends is defined as the front-back direction of the element body,
The line width direction of the signal conductor layer is defined as the element body left and right direction,
At least a portion of the first hole overlaps with the signal conductor layer when viewed in the vertical direction of the element body,
A surface on which the first insulating layer forms the first pores is defined as a first pore formation surface,
A surface of the second insulating layer forming the second pores is defined as a second pore formation surface,
The left portion of the first hole-forming surface has a portion located to the left of the second hole-forming surface in the left-right direction of the element in a cross section perpendicular to the longitudinal direction of the element.

According to the transmission line according to the present invention, transmission loss can be reduced.

FIG. 1 is an exploded perspective view of the transmission line 10. FIG. 2 is a cross-sectional view of the transmission line 10 taken along line AA in FIG. FIG. 3 is a left view of the electronic device 1 including the transmission line 10. FIG. 4 is a cross-sectional view of the transmission line 10a. FIG. 5 is a cross-sectional view of the transmission line 10b. FIG. 6 is a cross-sectional view of a transmission line 500 according to a comparative example. FIG. 7 is a diagram showing the electric field distribution of the first model. FIG. 8 is a diagram showing the electric field distribution of the second model. FIG. 9 is a diagram showing the electric field distribution at the left end of the signal conductor layer 22 of the first model. FIG. 10 is a diagram showing the electric field distribution at the left end of the signal conductor layer 22 of the second model. FIG. 11 is a graph showing the relationship between frequency and transmission loss for the first model and the second model. FIG. 12 is a cross-sectional view of the transmission line 10c. FIG. 13 is a cross-sectional view of the transmission line 10d. FIG. 14 is a cross-sectional view of the transmission line 10e. FIG. 15 is a cross-sectional view of the transmission line 10f. FIG. 16 is a cross-sectional view of the transmission line 10g. FIG. 17 is a cross-sectional view of the transmission line 10h. FIG. 18 is a cross-sectional view of the transmission line 10i. FIG. 19 is a cross-sectional view of the transmission line 10j. FIG. 20 is a cross-sectional view of the transmission line 10k. FIG. 21 is a cross-sectional view of the transmission line 10l. FIG. 22 is a cross-sectional view of the transmission line 10m. FIG. 23 is a cross-sectional view of the transmission line 10n. FIG. 24 is a cross-sectional view of the transmission line 10o.

(Embodiment)
[Transmission line structure]
Below, the structure of a transmission line 10 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of the transmission line 10. In FIG. 1, only representative interlayer connection conductors v1 and v2 among the plurality of interlayer connection conductors v1 and v2 are given reference numerals. FIG. 2 is a cross-sectional view of the transmission line 10 taken along line AA in FIG.

In this specification, direction is defined as follows. The direction in which the normal to the main surface of the element body 12 of the transmission line 10 extends is defined as the element body vertical direction. Further, the direction in which the signal conductor layer 22 of the transmission line 10 extends is defined as the front-back direction of the element body. Further, the line width direction of the signal conductor layer 22 is defined as the element body left-right direction. The element vertical direction, the element longitudinal direction, and the element horizontal direction are orthogonal to each other.

In the following, X is a component or member of the transmission line 10. In this specification, unless otherwise specified, each part of X is defined as follows. The front part of the X means the front half of the X. The rear part of the X means the rear half of the X. The left part of X means the left half of X. The right side of X means the right half of X. The upper part of X means the upper half of X. The lower part of X means the lower half of X. The front end of X means the front end of X. The rear end of X means the end of X in the rear direction. The left end of X means the left end of X. The right end of X means the right end of X. The upper end of X means the upper end of X. The lower end of X means the lower end of X. The front end of X means the front end of X and its vicinity. The rear end of X means the rear end of X and its vicinity. The left end of X means the left end of X and its vicinity. The right end of X means the right end of X and its vicinity. The upper end of X means the upper end of X and its vicinity. The lower end of X means the lower end of X and its vicinity.

First, the structure of the transmission line 10 will be explained with reference to FIG. Transmission line 10 transmits high frequency signals. The transmission line 10 is used to electrically connect two circuits in electronic devices such as smartphones. As shown in FIG. 1, the transmission line 10 includes an element body 12, protective layers 20a and 20b, a signal conductor layer 22, a first ground conductor layer 24, a second ground conductor layer 26, a third ground conductor layer 27, and a signal terminal. 28a, 28b, a plurality of interlayer connection conductors v1, v2, and interlayer connection conductors v3, v4.

The element body 12 has a plate shape. Therefore, the element body 12 has an upper main surface and a lower main surface (main surface). The upper main surface and the lower main surface (principal surface) of the element body 12 have normal lines extending in the vertical direction of the element body. The upper principal surface and lower principal surface of the element body 12 have a rectangular shape with long sides extending in the longitudinal direction of the element body. Therefore, the length of the element body 12 in the element body front-rear direction is longer than the element body 12 length in the element body left-right direction.

As shown in FIG. 1, the element body 12 includes insulator layers 16a to 16c, 18a, and 18b. The element body 12 has a structure in which insulator layers 16a, 18a, 16b, 18b, and 16c are laminated in this order from top to bottom in the vertical direction of the element body. The insulator layers 16a to 16c, 18a, and 18b have the same rectangular shape as the element body 12 when viewed in the vertical direction of the element body. The insulator layers 16a to 16c are flexible dielectric sheets. The material of the insulator layers 16a to 16c is, for example, thermoplastic resin. Examples of the thermoplastic resin include liquid crystal polymer, PTFE (polytetrafluoroethylene), and the like. Furthermore, the material of the insulator layers 16a to 16c may be polyimide. The insulator layer 18a is an adhesive layer that adheres the insulator layer 16a and the insulator layer 16b. The insulator layer 18a is a single-layer insulator layer. The insulator layer 18a being a single layer means that the insulator layer 18a does not have a structure in which a plurality of insulator layers are bonded together. The insulator layer 18b is an adhesive layer that adheres the insulator layer 16b and the insulator layer 16c. The insulator layer 18b is a single-layer insulator layer. The insulator layer 18b (second insulator layer) is provided below the insulator layer 18a (first insulator layer) in the vertical direction of the element body. In this specification, "the insulator layer 18b is provided below the insulator layer 18a in the vertical direction of the element body" refers to the following state. The insulator layer 18b is arranged below, in the vertical direction of the element, a plane (upper principal surface) passing through the upper end of the insulator layer 18a and perpendicular to the vertical direction of the element. In this case, the insulator layer 18a and the insulator layer 18b may or may not be lined up in the vertical direction of the element body. The insulator layers 18a and 18b are adhesive sheets, liquid adhesives applied by printing or the like, bonding sheets with viscosity and pasted in sheet form, or the like. The material of the insulator layers 18a and 18b is, for example, epoxy resin, fluorine resin, acrylic resin, or the like. In this way, the material of the insulator layer 18a (first insulator layer) is different from the material of the insulator layer 16b (third insulator layer) provided below the insulator layer 18a (first insulator layer) in the vertical direction of the element body. The material of the body layer) is different.

As shown in FIG. 1, the signal conductor layer 22 is provided below the insulator layer 18a (first insulator layer) in the element body 12 in the vertical direction of the element body. Further, the signal conductor layer 22 is provided above the insulator layer 18b (second insulator layer) in the element body 12 in the element body vertical direction. In this embodiment, the signal conductor layer 22 is provided on the upper main surface of the insulator layer 16b. Thereby, the signal conductor layer 22 is provided within the element body 12. The signal conductor layer 22 has a linear shape. The signal conductor layer 22 extends in the front-rear direction of the element body. The signal conductor layer 22 is located at the center of the upper main surface of the insulator layer 16b in the left-right direction of the element body.

The first ground conductor layer 24 is provided above the insulator layer 18a (first insulator layer) in the element body 12 in the element body vertical direction. In this embodiment, the first ground conductor layer 24 is provided on the upper main surface of the insulator layer 16a. Thereby, the first ground conductor layer 24 is located above the signal conductor layer 22 in the vertical direction of the element body. In this specification, "the first ground conductor layer 24 is located above the signal conductor layer 22 in the vertical direction of the element body" refers to the following state. At least a portion of the first ground conductor layer 24 is disposed within a region through which the signal conductor layer 22 passes when it moves in parallel in the upward direction of the element body. Therefore, the first ground conductor layer 24 may be located within a region through which the signal conductor layer 22 passes when it moves upward in parallel to the element body, or the first ground conductor layer 24 may be located within a region that the signal conductor layer 22 passes through when it moves in parallel in an upward direction to the element body. Sometimes it may protrude from the area through which it passes. In this embodiment, the first ground conductor layer 24 covers substantially the entire upper main surface of the insulator layer 16a. Therefore, the first ground conductor layer 24 protrudes from a region through which the signal conductor layer 22 passes when it moves in parallel in the upward direction of the element body. Further, the first ground conductor layer 24 overlaps with the signal conductor layer 22 when viewed in the vertical direction of the element body.

The second ground conductor layer 26 is provided in the element body 12 below the insulator layer 18b (second insulator layer) in the element body vertical direction. In this embodiment, the second ground conductor layer 26 is provided on the lower main surface of the insulator layer 16c. Thereby, the second ground conductor layer 26 is located below the signal conductor layer 22 in the vertical direction of the element body. In this embodiment, the second ground conductor layer 26 covers substantially the entire lower main surface of the insulator layer 16c. Thereby, the second ground conductor layer 26 overlaps with the signal conductor layer 22 when viewed in the vertical direction of the element body. As a result, the signal conductor layer 22, the first ground conductor layer 24, and the second ground conductor layer 26 have a stripline structure.

The third ground conductor layer 27 is provided in the element body 12 below the insulator layer 18a (first insulator layer) in the element body vertical direction. In this embodiment, the third ground conductor layer 27 is provided on the upper main surface of the insulator layer 16b. The third ground conductor layer 27 surrounds the signal conductor layer 22 when viewed in the vertical direction. Therefore, the third ground conductor layer 27 is provided on the left and right sides of the signal conductor layer 22 in the horizontal direction of the element body.

The plurality of interlayer connection conductors v1 and v2 electrically connect the first ground conductor layer 24, the second ground conductor layer 26, and the third ground conductor layer 27. More specifically, the plurality of interlayer connection conductors v1 and v2 penetrate the insulator layers 16a to 16c, 18a and 18b in the vertical direction of the element body. The upper ends of the plurality of interlayer connection conductors v1 and v2 are connected to the first ground conductor layer 24. The lower ends of the plurality of interlayer connection conductors v1 and v2 are connected to the second ground conductor layer 26. The intermediate portions of the plurality of interlayer connection conductors v1 and v2 are connected to the third ground conductor layer 27. The plurality of interlayer connection conductors v1 are provided on the left side of the signal conductor layer 22 in the lateral direction of the element body. The plurality of interlayer connection conductors v1 are arranged in a line at equal intervals in the front-rear direction of the element body. The plurality of interlayer connection conductors v2 are provided on the right side of the signal conductor layer 22 in the lateral direction of the element body. The plurality of interlayer connection conductors v2 are arranged in a line at equal intervals in the front-rear direction of the element body.

The signal terminal 28a is provided on the upper main surface of the element body 12. More specifically, the signal terminal 28a is provided at the front end of the upper main surface of the insulator layer 16a. The signal terminal 28a overlaps the front end of the signal conductor layer 22 when viewed in the vertical direction of the element body. However, the signal terminal 28a does not overlap with a first hole H1 and a second hole H2, which will be described later, when viewed in the vertical direction of the element body. The signal terminal 28a has a rectangular shape when viewed in the vertical direction of the element body. The first ground conductor layer 24 is not provided around the signal terminal 28a so that the signal terminal 28a is insulated from the first ground conductor layer 24.

The interlayer connection conductor v3 electrically connects the signal terminal 28a and the signal conductor layer 22. Specifically, the interlayer connection conductor v3 penetrates the insulator layers 16a and 18a in the vertical direction of the element body. The upper end of the interlayer connection conductor v3 is connected to the signal terminal 28a. The lower end of the interlayer connection conductor v3 is connected to the front end of the signal conductor layer 22. Thereby, the signal terminal 28a is electrically connected to the signal conductor layer 22. The high frequency signal is input/output to the signal conductor layer 22 via the signal terminal 28a.

Note that the signal terminal 28b and the interlayer connection conductor v4 have a structure that is laterally symmetrical to the signal terminal 28a and the interlayer connection conductor v3. Therefore, a description of the signal terminal 28b and the interlayer connection conductor v4 will be omitted.

The signal conductor layer 22, the first ground conductor layer 24, the second ground conductor layer 26, the third ground conductor layer 27, and the signal terminals 28a, 28b are formed on the upper main surface of the insulator layers 16a to 16c, for example. It is formed by etching a metal foil provided on the lower main surface. The metal foil is, for example, copper foil. Furthermore, the interlayer connection conductors v1 to v4 are, for example, through-hole conductors. The through-hole conductor is manufactured by forming through holes in the insulating layers 16a to 16c, 18a, and 18b and plating the through holes.

The protective layers 20a and 20b are flexible insulating layers. However, the protective layers 20a and 20b are not part of the element body 12. The protective layers 20a and 20b have the same rectangular shape as the element body 12 when viewed in the vertical direction of the element body.

The protective layer 20a covers substantially the entire upper main surface of the insulator layer 16a. Thereby, the protective layer 20a protects the first ground conductor layer 24. However, the protective layer 20a is provided with openings h1 to h6. The opening h1 overlaps with the signal terminal 28a when viewed in the vertical direction of the element body. Thereby, the signal terminal 28a is exposed to the outside from the transmission line 10 via the opening h1. The opening h2 is provided to the left of the opening h1 in the lateral direction of the element body. The opening h3 is provided to the right of the opening h1 in the lateral direction of the element body. Thereby, the first ground conductor layer 24 is exposed to the outside from the transmission line 10 via the openings h2 and h3. Note that the structures of the openings h4 to h6 are bilaterally symmetrical to the structures of the openings h1 to h3, respectively. Therefore, description of the openings h4 to h6 will be omitted.

Next, the first hole H1 and the second hole H2 will be explained with reference to FIGS. 1 and 2. The insulator layer 18a is provided with a first hole H1 that penetrates the insulator layer 18a in the vertical direction of the element body. More specifically, as shown in FIG. 1, the first hole H1 has a rectangular shape with long sides extending in the longitudinal direction of the element when viewed in the vertical direction of the element. The first hole H1 is provided in the center of the insulating layer 18a in the left-right direction of the element body. As a result, at least a portion of the first hole H1 overlaps with the signal conductor layer 22 when viewed in the vertical direction of the element body. The signal conductor layer 22 is located within the first hole H1, as shown in FIG. However, the front end and rear end of the signal conductor layer 22 do not overlap with the first hole H1 when viewed in the vertical direction of the element body. That is, the front end and rear end of the signal conductor layer 22 are not located within the first hole H1.

Further, the right end of the left part of the third ground conductor layer 27 is located within the first hole H1, as shown in FIG. The left end of the right part of the third ground conductor layer 27 is located within the first hole H1.

Here, as shown in FIG. 2, the surface of the insulator layer 18a on which the first holes H1 are formed is defined as the first hole formation surface S1. Further, the first hole forming surface S1 has a left portion S1L and a right portion S1R. Further, the left portion S1L of the first hole forming surface S1 has an upper end P1LU and a lower end P1LD. The right portion S1R of the first hole forming surface S1 has an upper end P1RU and a lower end P1RD.

The left portion S1L of the first hole forming surface S1 has an arcuate shape that projects to the left of the element body when viewed in the front-rear direction of the element body. That is, the left part S1L of the first pore forming surface S1 is the upper end P1LU of the left part S1L of the first pore forming surface S1 and the left part of the first pore forming surface S1 in a cross section perpendicular to the longitudinal direction of the element body. It has a curved shape so as to protrude leftward from the lower end P1LD of S1L. As a result, the center of the left portion S1L of the first hole forming surface S1 in the vertical direction of the element body is located at the farthest left in the left portion S1L. From the above, as shown in FIG. 2, the left part S1L of the first pore forming surface S1 is the upper end P1LU of the left part S1L of the first pore forming surface S1 and the first It has a portion located to the left of the lower end P1LD of the left portion S1L of the hole forming surface S1 in the left-right direction of the element body.

The right portion S1R of the first hole forming surface S1 has an arcuate shape that protrudes to the right of the element body when viewed in the front-rear direction of the element body. That is, the right part S1R of the first pore forming surface S1 is the upper end P1RU of the right part S1R of the first pore forming surface S1 and the right part of the first pore forming surface S1 in a cross section perpendicular to the longitudinal direction of the element body. It has a curved shape so as to protrude rightward from the lower end P1RD of S1R. As a result, the center of the right portion S1R of the first hole forming surface S1 in the vertical direction of the element body is located at the rightmost position in the right portion S1R. As described above, as shown in FIG. It has a portion located to the right in the lateral direction of the element body from the lower end P1RD of the right portion S1R of the hole forming surface S1.

The insulator layer 18b is provided with a second hole H2 that penetrates the insulator layer 18b in the vertical direction of the element body. More specifically, as shown in FIG. 1, the second hole H2 has a rectangular shape with long sides extending in the longitudinal direction of the element when viewed in the vertical direction of the element. The second hole H2 is provided in the center of the insulating layer 18b in the left-right direction of the element body. As a result, at least a portion of the second hole H2 overlaps with the signal conductor layer 22 when viewed in the vertical direction of the element body. However, the front end and rear end of the signal conductor layer 22 do not overlap with the second holes H2 when viewed in the vertical direction of the element body.

Here, the surface of the insulator layer 18b on which the second holes H2 are formed is defined as the second hole formation surface S2. Further, the second hole forming surface S2 has a left portion S2L and a right portion S2R. Further, the left portion S2L of the second hole forming surface S2 has an upper end P2LU and a lower end P2LD. The right portion S2R of the second hole forming surface S2 has an upper end P2RU and a lower end P2RD.

The left portion S2L of the second hole forming surface S2 has an arcuate shape that protrudes to the left of the element body when viewed in the front-rear direction of the element body. That is, the left part S2L of the second pore forming surface S2 is the upper end P2LU of the left part S2L of the second pore forming surface S2 and the left part of the second pore forming surface S2 in a cross section orthogonal to the front-rear direction of the element body. It has a curved shape so as to protrude leftward from the lower end P2LD of S2L. As a result, the center of the left portion S2L of the second hole forming surface S2 in the vertical direction of the element body is located at the farthest left in the left portion S2L. From the above, as shown in FIG. 2, the left part S2L of the second pore forming surface S2 is the upper end P2LU of the left part S2L of the second pore forming surface S2 and the second It has a portion located to the left of the lower end P2LD of the left portion S2L of the hole forming surface S2 in the lateral direction of the element body.

The right portion S2R of the second hole forming surface S2 has an arcuate shape that protrudes to the right of the element body when viewed in the front-rear direction of the element body. That is, the right part S2R of the second pore forming surface S2 is the upper end P2RU of the right part S2R of the second pore forming surface S2 and the right part of the second pore forming surface S2 in a cross section perpendicular to the longitudinal direction of the element body. It has a curved shape so as to protrude rightward from the lower end P2RD of S2R. As a result, the center of the right portion S2R of the second hole forming surface S2 in the vertical direction of the element body is located at the rightmost position in the right portion S2R. From the above, as shown in FIG. 2, the right part S1R of the second pore forming surface S2 is the upper end P2RU of the right part S2R of the second pore forming surface S2 and the second It has a portion located to the right in the lateral direction of the element body from the lower end P2RD of the right portion S2R of the hole forming surface S2.

A method for forming the first holes H1 and second holes H2 as described above will be explained. Methods for forming the first pores H1 and second pores H2 include a thermal expansion method, a volatilization method, and a pressure method.

The thermal expansion method utilizes the difference between the linear expansion coefficients of the insulator layers 16a to 16c and the linear expansion coefficients of the insulator layers 18a and 18b. When the insulator layers 16a to 16c, 18a, and 18b are thermocompression bonded, the first holes H1 become smaller due to the pressure of the thermocompression bonding. Here, the linear expansion coefficients of the insulator layers 18a and 18b are larger than the linear expansion coefficients of the insulator layers 16a to 16c. Therefore, when the thermocompression bonding of the insulator layers 16a to 16c, 18a, and 18b is completed and the insulator layers 16a to 16c, 18a, and 18b are cooled, the insulator layers 18a and 18b are larger than the insulator layers 16a to 16c. Shrink. However, the upper main surface of the insulator layer 18a is adhered to the lower main surface of the insulator layer 16a. The lower main surface of the insulator layer 18a is adhered to the upper main surface of the insulator layer 16b. Therefore, the upper main surface and the lower main surface of the insulator layer 18a are restrained by the lower main surface of the insulator layer 16a and the upper main surface of the insulator layer 16b, respectively. Therefore, the left portion S1L of the first hole-forming surface S1 is deformed so as to protrude to the left of the element body. Similarly, the right portion S1R of the first hole forming surface S1 is deformed so as to protrude to the right of the element body. Similarly, the left portion S2L of the second hole forming surface S2 is deformed so as to protrude to the left of the element body. Similarly, the right portion S2R of the second hole-forming surface S2 is deformed so as to protrude to the right of the element body. As a result, first holes H1 and second holes H2 are formed.

The volatilization method utilizes the fact that components contained in the insulating layers 18a and 18b are volatilized by thermocompression bonding of the insulating layers 16a to 16c, 18a and 18b. More specifically, when the insulator layers 16a to 16c, 18a, and 18b are thermocompression bonded, the first pores H1 and the second pores H2 become smaller due to the pressure of the thermocompression bonding. Here, the components contained in the insulator layers 18a, 18b are volatilized by thermocompression bonding of the insulator layers 16a to 16c, 18a, and 18b. Therefore, the volume reduction rate of the insulator layers 18a, 18b before and after thermocompression bonding is greater than the volume reduction rate of the insulator layers 16a to 16c before and after thermocompression bonding. However, the upper main surface of the insulator layer 18a is adhered to the lower main surface of the insulator layer 16a. The lower main surface of the insulator layer 18a is adhered to the upper main surface of the insulator layer 16b. Therefore, the upper main surface and the lower main surface of the insulator layer 18a are restrained by the lower main surface of the insulator layer 16a and the upper main surface of the insulator layer 16b, respectively. Therefore, the left portion S1L of the first hole-forming surface S1 is deformed so as to protrude to the left of the element body. Similarly, the right portion S1R of the first hole forming surface S1 is deformed so as to protrude to the right of the element body. Similarly, the left portion S2L of the second hole forming surface S2 is deformed so as to protrude to the left of the element body. Similarly, the right portion S2R of the second hole-forming surface S2 is deformed so as to protrude to the right of the element body. As a result, first holes H1 and second holes H2 are formed.

The pressure method utilizes the expansion of the first holes H1 and second holes H2 after thermocompression bonding of the insulator layers 16a to 16c, 18a, and 18b. More specifically, when the insulator layers 16a to 16c, 18a, and 18b are thermocompression bonded, the first pores H1 and the second pores H2 become smaller due to the pressure of the thermocompression bonding. When the thermocompression bonding of the insulator layers 16a to 16c, 18a, and 18b is completed, the pressure applied to the first holes H1 and the second holes H2 becomes smaller, so the first holes H1 and the second holes H2 become larger. . However, the upper main surface of the insulator layer 18a is adhered to the lower main surface of the insulator layer 16a. The lower main surface of the insulator layer 18a is adhered to the upper main surface of the insulator layer 16b. Therefore, the upper main surface and the lower main surface of the insulator layer 18a are restrained by the lower main surface of the insulator layer 16a and the upper main surface of the insulator layer 16b, respectively. Therefore, the left portion S1L of the first hole-forming surface S1 is deformed so as to protrude to the left of the element body. Similarly, the right portion S1R of the first hole forming surface S1 is deformed so as to protrude to the right of the element body. Similarly, the left portion S2L of the second hole forming surface S2 is deformed so as to protrude to the left of the element body. Similarly, the right portion S2R of the second hole-forming surface S2 is deformed so as to protrude to the right of the element body. As a result, first holes H1 and second holes H2 are formed.

[Structure of electronic equipment]
Next, the structure of the electronic device 1 including the transmission line 10 will be described with reference to the drawings. FIG. 3 is a left view of the electronic device 1 including the transmission line 10. The electronic device 1 is, for example, a portable wireless communication terminal. The electronic device 1 is, for example, a smartphone.

The transmission line 10 is bent as shown in FIG. "The transmission line 10 is bent" means that the transmission line 10 is deformed and bent by applying an external force to the transmission line 10. Hereinafter, the section in which the transmission line 10 is bent will be referred to as a bending section A2. The sections in which the transmission line 10 is not bent are referred to as non-bending sections A1 and A3. Then, the x-axis, y-axis, and z-axis in the electronic device 1 are defined as follows. The x-axis is the longitudinal direction of the element body in the non-bending section A1. The y-axis is the horizontal direction of the element body in the non-bending section A1. The z-axis is the vertical direction of the element body in the non-bending section A1. The non-bending section A1, the bending section A2, and the non-bending section A3 are arranged in this order toward the positive direction of the x-axis.

As shown in FIG. 3, the bending section A2 is bent in the z-axis direction. Therefore, the vertical direction of the element body and the longitudinal direction of the element body differ depending on the position of the transmission line 10, as shown in FIG. In the non-bending section A1 and the non-bending section A3 (for example, the position (1)) where the element body 12 is not bent, the element body vertical direction and the element body front-rear direction coincide with the z-axis direction and the x-axis direction, respectively. do. On the other hand, in the bending section A2 (for example, the position (2)) where the element body 12 is bent, the element body up-down direction and the element body front-rear direction do not coincide with the z-axis direction and the x-axis direction, respectively.

As shown in FIG. 3, the electronic device 1 includes a transmission line 10, connectors 30a, 30b, 102a, 102b, and circuit boards 100, 110.

The circuit boards 100 and 110 have a plate shape. Circuit board 100 has main surfaces S5 and S6. The main surface S5 is located on the negative side of the z-axis from the main surface S6. Circuit board 110 has main surfaces S11 and S12. The main surface S11 is located on the negative side of the z-axis from the main surface S12. The circuit boards 100 and 110 include a wiring conductor layer, a ground conductor layer, electrodes, etc. (not shown).

Each of the connectors 30a and 30b is mounted on the main surface (upper main surface) on the positive direction side of the z-axis of the non-bending section A1 and the non-bending section A3. More specifically, the connector 30a is mounted on the signal terminal 28a and the first ground conductor layer 24 exposed through the openings h1 to h3. The connector 30b is mounted on the signal terminal 28b and the first ground conductor layer 24 exposed through the openings h4 to h6.

Each of the connectors 102a and 102b is mounted on the main surface S5 of the circuit board 100 and the main surface S11 of the circuit board 110. Connectors 102a and 102b are connected to connectors 30a and 30b, respectively. Thereby, the transmission line 10 electrically connects the circuit board 100 and the circuit board 110.

[effect]
According to the transmission line 10, transmission loss of the transmission line 10 can be reduced. More specifically, the insulator layer 18a is provided with a first hole H1 that penetrates the insulator layer 18a in the vertical direction of the element body. Air with a low dielectric constant exists within the first holes H1. At least a portion of the first hole H1 overlaps with the signal conductor layer 22 when viewed in the vertical direction of the element body. Therefore, the dielectric constant around the signal conductor layer 22 becomes low. As a result, in the transmission line 10, the occurrence of dielectric loss in the high frequency signal transmitted through the signal conductor layer 22 is suppressed, so that the transmission loss of the transmission line 10 is reduced. The second holes H2 also contribute to reducing the transmission loss of the transmission line 10 for the same reason as the first holes H1.

Further, according to the transmission line 10, the transmission loss of the transmission line 10 can be reduced while suppressing peeling between the insulator layer 16a and the insulator layer 18a and between the insulator layer 16b and the insulator layer 18a. can be achieved. More specifically, as shown in FIG. 2, the left portion S1L of the first hole forming surface S1 is the upper end P1LU and It has a portion located to the left of the lower end P1LD of the left portion S1L of the first hole forming surface S1 in the lateral direction of the element body. As a result, the upper end P1LU of the left portion S1L of the first hole-forming surface S1 becomes separated from the left surface of the element body 12. That is, the area where the insulator layer 16a and the insulator layer 18a are bonded becomes wider. Similarly, the lower end P1LD of the left portion S1L of the first hole forming surface S1 becomes separated from the left surface of the element body 12. That is, the area where the insulator layer 16b and the insulator layer 18a are bonded becomes wider. As a result, separation between the insulator layer 16a and the insulator layer 18a, and separation between the insulator layer 16b and the insulator layer 18a are suppressed.

Furthermore, as shown in FIG. 2, the left portion S1L of the first hole forming surface S1 is the upper end P1LU of the left portion S1L of the first hole forming surface S1 and the first hole in a cross section orthogonal to the front-rear direction of the element body. It has a portion located to the left of the lower end P1LD of the left portion S1L of the hole forming surface S1 in the lateral direction of the element body. As a result, the left portion S1L of the first hole forming surface S1 has a shape that protrudes to the left of the element body in a cross section perpendicular to the front-rear direction of the element body. Therefore, the volume of the first hole H1 is large. As a result, in the transmission line 10, the occurrence of dielectric loss in the high frequency signal transmitted through the signal conductor layer 22 is suppressed, so that the transmission loss of the transmission line 10 is reduced. For the same reason as the first hole H1, the second hole H2 also suppresses separation between the insulator layer 16b and the insulator layer 18b, and suppresses separation between the insulator layer 16c and the insulator layer 18b, and suppresses transmission. This contributes to reducing the transmission loss of the line 10.

Note that the right portion S1R of the first hole forming surface S1 has a shape that is bilaterally symmetrical to the left portion S1L of the first hole forming surface S1. Thereby, according to the transmission line 10, the transmission loss of the transmission line 10 is reduced while suppressing peeling between the insulator layer 16a and the insulator layer 18a and between the insulator layer 16b and the insulator layer 18a. can be achieved.

Further, the left portion S1L of the first hole forming surface S1 has a shape that protrudes to the left of the element body in a cross section perpendicular to the front-rear direction of the element body. The left portion S1L of the first hole forming surface S1 is curved. As a result, when force is applied to the transmission line 10, concentration of stress on a portion of the left portion S1L is suppressed. That is, the transmission line 10 is less likely to be damaged.

Further, according to the transmission line 10, since the first hole H1 is provided, the element body 12 is easily deformed. As a result, the transmission line 10 can be easily bent and used. Additionally, the amount of adhesive used in the transmission line 10 is reduced. Therefore, the manufacturing cost of the transmission line 10 can be reduced and the weight of the transmission line 10 can be reduced. Note that, like the first holes H1, the second holes H2 also contribute to easily deforming the element body 12 and reducing the amount of adhesive.

Moreover, according to the transmission line 10, transmission loss of the transmission line 10 can be reduced for the following reasons. More specifically, an electric field is radiated from the signal conductor layer 22. The electric field more easily passes through the insulator layer 16a having a higher dielectric constant than the first holes H1 having a lower dielectric constant. Therefore, when the insulator layer 16a is present near the signal conductor layer 22, the electric field radiated by the signal conductor layer 22 extends to the left of the element body and passes through the insulator layer 16a. In this case, on the left side of the signal conductor layer 22, the electric field is concentrated at the corner of the signal conductor layer 22. Such electric field concentration causes current concentration at the corners of the signal conductor layer 22. As a result, the transmission loss of the transmission line 10 may increase.

Therefore, as shown in FIG. 2, the left portion S1L of the first hole forming surface S1 is the upper end P1LU of the left portion S1L of the first hole forming surface S1 and the first hole It has a portion located to the left of the lower end P1LD of the left portion S1L of the hole forming surface S1 in the lateral direction of the element body. Therefore, the left portion S1L of the first hole-forming surface S1 protrudes in the direction away from the signal conductor layer 22. This reduces the amount of insulator layer 18a located near signal conductor layer 22. Therefore, the electric field emitted by the signal conductor layer 22 spreads toward the upper left of the element body. In this case, on the left side of the signal conductor layer 22, concentration of the electric field at the corners of the signal conductor layer 22 is suppressed. As a result, according to the transmission line 10, transmission loss of the transmission line 10 can be reduced.

In the transmission line 10, since the first hole H1 is located near the interlayer connection conductors v1 and v2, capacitance is less likely to be formed between the signal conductor layer 22 and the interlayer connection conductors v1 and v2. Thereby, the signal conductor layer 22 and the interlayer connection conductors v1 and v2 can be brought closer to each other. Note that "the first hole H1 is located near the interlayer connection conductor v1" means, for example, the left end of the first hole H1 and the interlayer connection conductor located to the left of the first hole H1 in the horizontal direction of the element body. This means that the distance to v1 is shorter than the distance between interlayer connection conductor v1 and signal conductor layer 22.

In the transmission line 10, since the first hole H1 is located near the interlayer connection conductors v1 and v2, the wavelength of the high frequency signal transmitted through the plurality of interlayer connection conductors v1 and v2 becomes long. As a result, the intervals between the plurality of interlayer connection conductors v1 and the intervals between the plurality of interlayer connection conductors v2 become longer.

Water vapor or the like in the air may oxidize conductor layers such as the signal line conductor layer 20 and deteriorate signal characteristics. In the transmission line 10, since the contact area between the air in the first hole H1 and the resin 18a increases, the adsorptivity of unnecessary gases contained in the air in the resin 18a increases, and water vapor, etc. contained in the air decreases. In this way, according to the transmission line 10, deterioration of characteristics can be suppressed by reducing water vapor and the like in the air.

In the transmission line 10, peeling of the insulator layer 16b and the insulator layer 18a is suppressed. More specifically, if the right end of the left part of the third ground conductor layer 27 is not located within the first hole H1, the right end of the left part of the third ground conductor layer 27 is not located within the first hole H1. It is located to the left of the left side S1L of the surface S1. In this case, a gap is formed between the insulating layer 16b and the insulating layer 18a near the lower end P1LD of the left portion S1L of the first hole forming surface S1. Such a gap causes separation between the insulator layer 16b and the insulator layer 18a. Therefore, the right end of the left portion of the third ground conductor layer 27 is located within the first hole H1. That is, a portion of the third ground conductor layer 27 is located within the first hole H1. As a result, no gap is formed between the insulating layer 16b and the insulating layer 18a near the lower end P1LD of the left portion S1L of the first hole forming surface S1. As a result, in the transmission line 10, separation of the insulating layer 16b and the insulating layer 18a is suppressed.

Furthermore, in the transmission line 10, the signal conductor layer 22 is located within the first hole H1, as shown in FIG. As a result, the signal conductor layer 22 comes into contact with air, so that the dielectric constant around the signal conductor layer 22 decreases. As a result, the occurrence of dielectric loss in the high frequency signal transmitted through the signal conductor layer 22 is suppressed.

Further, in the transmission line 10, the signal terminal 28a does not overlap with the first hole H1 and the second hole H2, which will be described later, when viewed in the vertical direction of the element body. This suppresses damage to the transmission line 10 due to stress during thermocompression bonding during manufacture of the transmission line 10.

(First modification)
A transmission line 10a according to a first modification will be described below with reference to the drawings. FIG. 4 is a cross-sectional view of the transmission line 10a.

The transmission line 10a differs from the transmission line 10 in the positions where the first ground conductor layer 24 and the second ground conductor layer 26 are provided. More specifically, the first ground conductor layer 24 is provided on the lower main surface of the insulator layer 16a. Thereby, the first ground conductor layer 24 faces the first hole H1. The second ground conductor layer 26 is provided on the upper main surface of the insulator layer 16c. Thereby, the second ground conductor layer 26 faces the second hole H2. The rest of the structure of the transmission line 10a is the same as the transmission line 10, so the explanation will be omitted. Furthermore, the transmission line 10a can have the same effects as the transmission line 10.

(Second modification)
A transmission line 10b according to a second modification will be described below with reference to the drawings. FIG. 5 is a cross-sectional view of the transmission line 10b. FIG. 6 is a cross-sectional view of a transmission line 500 according to a comparative example.

The transmission line 10b differs from the transmission line 10 in that it does not include insulator layers 16a, 16c, protective layers 20a, 20b, and interlayer connection conductors v1, v2. In this way, the insulator layers 16a, 16c, the protective layers 20a, 20b, and the interlayer connection conductors v1, v2 are not essential components. Note that in the transmission line 10b, the first ground conductor layer 24 is attached to the upper main surface of the insulator layer 18a by, for example, a transfer method. The second ground conductor layer 26 is attached to the lower main surface of the insulator layer 18b by, for example, a transfer method. The other structure of the transmission line 10b is the same as that of the transmission line 10, so the explanation will be omitted. Furthermore, the transmission line 10b can have the same effects as the transmission line 10.

The inventor of the present application conducted a computer simulation as described below in order to clarify the effect produced by the transmission line 10b. Specifically, a first model having the structure of the transmission line 10b and a second model having the structure of the transmission line 500 were created. The difference between the first model and the second model is the shape of the first hole H1 and the second hole H2. Note that the distance L1 between the upper end P1LU and the upper end P1RU in the first model is equal to the distance L2 between the upper end P1LU and the upper end P1RU in the second model. The inventor of this application caused a computer to calculate the distribution of the electric field around the signal conductor layer 22 using the first model and the second model. The inventor also caused a computer to calculate the relationship between the frequencies of the first model and the second model and the transmission losses of the first model and the second model. At this time, the inventor of the present application performed the calculation under the condition that the first ground conductor layer 24 and the second ground conductor layer 26 were electrically connected and a high frequency signal was applied between them and the signal conductor layer 22.

FIG. 7 is a diagram showing the electric field distribution of the first model. FIG. 8 is a diagram showing the electric field distribution of the second model. In FIGS. 7 and 8, dark colored parts mean areas where the electric field intensity is high, and light colored parts mean areas where the electric field intensity is low. Comparing FIGS. 7 and 8, it can be seen that the region of low electric field strength in the first model is wider than the region of low electric field strength in the second model. It can also be seen that the electric field strength of the insulator layer, which has a larger dielectric loss than air, is smaller in the first model than in the second model. This is considered to be because the volumes of the first holes H1 and second holes H2 in the first model are larger than the volumes of the first holes H1 and second holes H2 in the second model. In this way, when the region of low electric field strength in the first model becomes wider than the region of low electric field strength in the second model, and the electric field strength of the insulator layer decreases, the transmission loss of high-frequency signals that occurs in the first model increases. is smaller than the high frequency signal transmission loss that occurs in the second model.

FIG. 9 is a diagram showing the electric field distribution at the left end of the signal conductor layer 22 of the first model. FIG. 10 is a diagram showing the electric field distribution at the left end of the signal conductor layer 22 of the second model. Comparing FIGS. 9 and 10, it can be seen that concentration of the electric field at the corners of the signal conductor layer 22 is suppressed more in the first model than in the second model. Thereby, in the first model, concentration of current at the corners of the signal conductor layer 22 is suppressed. As a result, the transmission loss of high frequency signals is reduced in the first model compared to the second model.

FIG. 11 is a graph showing the relationship between the frequencies of the first model and the second model and the transmission losses of the first model and the second model. The horizontal axis is the frequency of the high frequency signal transmitted through the signal conductor layer 22. The vertical axis is the transmission loss of the transmission line per meter of the first model and the second model. According to FIG. 11, it can be seen that the transmission loss of the first model (transmission line 10a) is smaller than the transmission loss of the second model (transmission line 500).

(Third modification)
A transmission line 10c according to a third modification will be described below with reference to the drawings. FIG. 12 is a cross-sectional view of the transmission line 10c.

The transmission line 10c differs from the transmission line 10a in that it further includes an insulator layer 16d and third ground conductor layers 27a and 27b. More specifically, the insulator layer 16d is provided between the insulator layer 18a and the insulator layer 16b. Thereby, the signal conductor layer 22 is located between the insulator layer 16d and the insulator layer 16b. That is, the signal conductor layer 22 is not located within the first hole H1. As described above, by surrounding the signal conductor layer 22 with the insulator layers 16b and 16d, short-circuiting of the signal conductor layer 22 with other conductor layers is suppressed. Furthermore, deterioration of the signal conductor layer 22 due to oxidation or the like is suppressed.

Further, the third ground conductor layer 27a is provided on the upper main surface of the insulator layer 16b. The third ground conductor layer 27b is provided on the lower main surface of the insulator layer 16d. The rest of the structure of the transmission line 10c is the same as that of the transmission line 10a, so a description thereof will be omitted. The transmission line 10c can have the same effects as the transmission line 10.

Further, a third ground conductor layer 27a is located above the signal conductor layer 22 in the vertical direction of the element, and a third ground conductor layer 27b is located below the signal conductor layer 22 in the vertical direction of the element. This improves the shielding properties for the signal conductor layer 22.

(Fourth modification)
A transmission line 10d according to a fourth modification will be described below with reference to the drawings. FIG. 13 is a cross-sectional view of the transmission line 10d.

The transmission line 10d differs from the transmission line 10c in the positions where the first ground conductor layer 24 and the second ground conductor layer 26 are provided. More specifically, the first ground conductor layer 24 is provided on the upper main surface of the insulator layer 16a. The second ground conductor layer 26 is provided on the lower main surface of the insulator layer 16c. The rest of the structure of the transmission line 10d is the same as that of the transmission line 10c, so a description thereof will be omitted. Further, the transmission line 10d can have the same effects as the transmission line 10c.

(Fifth modification)
A transmission line 10e according to a fifth modification will be described below with reference to the drawings. FIG. 14 is a cross-sectional view of the transmission line 10e.

The transmission line 10e differs from the transmission line 10 in the thickness of the insulator layers 16a, 16c, 18a, and 18b and the presence or absence of holes H3 and H4. More specifically, in the transmission line 10e, the thickness of the insulator layers 18a, 18b is smaller than the thickness of the insulator layers 16a, 16c. Further, the holes H3 and H4 are provided in the insulator layers 16a and 16c, respectively. The holes H3 and H4 respectively penetrate the insulator layers 16a and 16c in the vertical direction of the element body. Further, the hole H3 is connected to the first hole H1. The hole H4 is connected to the second hole H2. The rest of the structure of the transmission line 10e is the same as the transmission line 10, so the explanation will be omitted.

The insulator layers 18a and 18b are adhesive layers. Therefore, the thickness of the insulating layers 18a and 18b tends to change when the element body 12 is crimped. Therefore, the thickness of the insulator layers 18a, 18b is smaller than the thickness of the insulator layers 16a, 16b. The amount of change in the thickness of the insulator layers 18a, 18b when the element body 12 is crimped is reduced. This suppresses variations in the sizes of the first holes H1 and the second holes H2 in the vertical direction of the element body.

(Sixth variation)
A transmission line 10f according to a sixth modification will be described below with reference to the drawings. FIG. 15 is a cross-sectional view of the transmission line 10f.

The transmission line 10f differs from the transmission line 10e in that the first hole H11, the second hole H12, and the holes H13 and H14 are provided in the element body 12. More specifically, the first hole H1, the second hole H2, and the holes H3 and H4 are arranged to the left of the center of the element body 12 in the element body lateral direction. Further, the first hole H11, the second hole H12, and the holes H13 and H14 are arranged to the right of the center of the element body 12 in the element body lateral direction. Each of the first hole H11, the second hole H12, and the holes H13, H14 has a structure that is symmetrical to the first hole H1, the second hole H2, and the holes H3, H4. The rest of the structure of the transmission line 10f is the same as that of the transmission line 10e, so a description thereof will be omitted. Moreover, the transmission line 10f can have the same effect as the transmission line 10e.

According to the transmission line 10f, some of the insulator layers 16a to 16c, 18a, and 18b are formed by the first hole H1, the second hole H2, the holes H3, H4, the first hole H11, and the second hole. It exists between H12 and holes H13 and H14. This causes some of the insulator layers 16a to 16c, 18a, and 18b to function as pillars. As a result, when the transmission line 10f is bent, deformation of the first holes H1, H11, the second holes H2, H12, and the holes H3, H4, H13, H14 is suppressed.

(Seventh modification)
A transmission line 10g according to a seventh modification will be described below with reference to the drawings. FIG. 16 is a cross-sectional view of the transmission line 10g.

The transmission line 10g differs from the transmission line 10f in that the first hole H21, the second hole H22, and the holes H23 and H24 are provided in the element body 12. More specifically, the first hole H21, the second hole H22, and the holes H23, H24 are arranged to the right of the first hole H1, the second hole H2, and the holes H3, H4 in the lateral direction of the element body. has been done. The first hole H21, the second hole H22, and the holes H23 and H24 are arranged to the left of the first hole H11, the second hole H12, and the holes H13 and H14 in the lateral direction of the element body. Each of the first hole H21, the second hole H22, and the holes H23, H24 has the same structure as the first hole H1, the second hole H2, and the holes H3, H4. The rest of the structure of the transmission line 10g is the same as that of the transmission line 10f, so a description thereof will be omitted. Moreover, the transmission line 10g can have the same effect as the transmission line 10f.

According to the transmission line 10g, an insulating layer 16a is provided between the first hole H1, the second hole H2, the holes H3, H4, and the first hole H21, the second hole H22, and the holes H23, H24. Parts of ~16c, 18a, and 18b are present. Insulator layers 16a to 16c, 18a, 18b are formed between the first hole H11, the second hole H12, the holes H13, H14 and the first hole H21, the second hole H22, and the holes H23, H24. Some exist. This causes some of the insulator layers 16a to 16c, 18a, and 18b to function as pillars. As a result, when the transmission line 10g is bent, the first holes H1, H11, H21, the second holes H2, H12, H22, and the holes H3, H4, H13, H14, H23, H24 are deformed. is suppressed.

(Eighth modification)
A transmission line 10h according to an eighth modification will be described below with reference to the drawings. FIG. 17 is a cross-sectional view of the transmission line 10h.

The transmission line 10h differs from the transmission line 10e in that it further includes insulator layers 18c and 18d, and that the first hole H31 and the second hole H41 are provided in the element body 12. The insulator layer 18c is provided above the insulator layer 16a in the vertical direction of the element body. Therefore, the first ground conductor layer 24 is provided on the upper main surface of the insulator layer 18c. The insulator layer 18d is provided below the insulator layer 16c in the vertical direction of the element body. Therefore, the second ground conductor layer 26 is provided on the lower main surface of the insulator layer 18d.

The first holes H31 penetrate the insulating layer 18c in the vertical direction of the element body. The shape of the first hole H31 is the same as the first hole H1. The first hole H31 is connected to the hole H3. The second hole H41 penetrates the insulator layer 18d in the vertical direction of the element body. The shape of the second hole H41 is the same as that of the first hole H1. The second hole H41 is connected to the hole H4. The rest of the structure of the transmission line 10h is the same as that of the transmission line 10e, so a description thereof will be omitted. Moreover, the transmission line 10h can have the same effect as the transmission line 10e.

The insulator layers 18a to 18d are adhesive layers. Therefore, the thickness of the insulating layers 18a to 18d tends to change when the element body 12 is crimped. Therefore, the thickness of the insulator layers 18a to 18d is smaller than the thickness of the insulator layers 16a and 16c. The amount of change in the thickness of the insulating layers 18a to 18d when the element body 12 is crimped is reduced. This suppresses variations in the sizes of the first holes H1, H31, the second holes H2, H41, and the holes H3, H4 in the vertical direction of the element body.

Moreover, if a material having a lower dielectric constant or a lower dielectric loss tangent than the material of the insulating layer 16b is used for the insulating layers 16a and 16c, the transmission loss of the transmission line 10h can be reduced.

(9th modification)
A transmission line 10i according to a ninth modification will be described below with reference to the drawings. FIG. 18 is a cross-sectional view of the transmission line 10i.

The transmission line 10i differs from the transmission line 10c in that it includes a plurality of conductive objects 200 instead of the interlayer connection conductors v1 and v2. More specifically, the plurality of conductive objects 200 are, for example, metal balls whose surfaces are covered with solder or conductive adhesive. The diameters of the metal spheres of the plurality of conductive objects 200 are uniform. The plurality of conductors 200 are provided in the insulator layer 18a (first insulator layer). The plurality of conductors 200 electrically connect the first ground conductor layer 24 and the third ground conductor layer 27a.

The plurality of conductors 200 are provided on the insulator layer 18b. The plurality of conductors 200 electrically connect the second ground conductor layer 26 and the third ground conductor layer 27b. The plurality of conductive objects 200 are joined to the second ground conductor layer 26 and the third ground conductor layer 27b. The rest of the structure of the transmission line 10i is the same as that of the transmission line 10c, so a description thereof will be omitted. Moreover, the transmission line 10i can have the same effect as the transmission line 10c.

According to the transmission line 10i, the interlayer connection conductors v1 and v2 are no longer necessary. Therefore, a plating process for forming interlayer connection conductors v1 and v2 is not necessary. Therefore, the plating solution will not enter into the transmission line 10i.

According to the transmission line 10i, the distance between the insulator layer 16a and the insulator layer 16d is substantially determined by the diameters of the metal balls of the plurality of conductors 200. Similarly, the distance between the insulating layer 16b and the insulating layer 16c is substantially determined by the diameters of the metal balls of the plurality of conductive objects 200. This suppresses variations in the distance between the insulator layer 16a and the insulator layer 16d and the distance between the insulator layer 16b and the insulator layer 16c. That is, variation in the size of the first hole H1 in the vertical direction of the element body and the size of the second hole H2 in the vertical direction of the element body is suppressed.

(10th modification)
A transmission line 10j according to a tenth modification will be described below with reference to the drawings. FIG. 19 is a cross-sectional view of the transmission line 10j.

Transmission line 10j differs from transmission line 10c in that it further includes insulator layers 16e, 16f and conductor layers 150, 152, 160, 162. More specifically, the insulator layer 16e is provided above the insulator layer 16a in the vertical direction of the element body. The insulator layer 16f is provided below the insulator layer 16c in the vertical direction of the element body. The conductor layer 150 is provided on the lower main surface of the insulator layer 16e. The conductor layer 152 is provided on the upper main surface of the insulator layer 16e. The conductor layer 160 is provided on the upper main surface of the insulator layer 16f. The conductor layer 162 is provided on the lower main surface of the insulator layer 16f. The conductor layers 150, 152, 160, and 162 are signal wiring and ground conductors. By providing the conductor layers 150, 152, 160, and 162 in this way, an electric circuit is added to the transmission line 10j. The rest of the structure of the transmission line 10j is the same as that of the transmission line 10c, so a description thereof will be omitted. Moreover, the transmission line 10j can have the same effect as the transmission line 10c.

(11th modification)
A transmission line 10k according to an eleventh modification will be described below with reference to the drawings. FIG. 20 is a cross-sectional view of the transmission line 10k.

The transmission line 10k differs from the transmission line 10j in that it includes a plurality of conductive objects 200 instead of the interlayer connection conductors v1 and v2. More specifically, the diameters of the plurality of conductors 200 are uniform. The plurality of conductors 200 are provided in the insulator layer 18a (first insulator layer). The plurality of conductors 200 electrically connect the first ground conductor layer 24 and the third ground conductor layer 27a.

The plurality of conductors 200 are provided on the insulator layer 18b. The plurality of conductors 200 electrically connect the second ground conductor layer 26 and the third ground conductor layer 27b. The rest of the structure of the transmission line 10k is the same as the transmission line 10j, so the explanation will be omitted. Moreover, the transmission line 10k can have the same effect as the transmission line 10j.

(12th modification)
A transmission line 10l according to a twelfth modification will be described below with reference to the drawings. FIG. 21 is a cross-sectional view of the transmission line 10l.

The transmission line 10l does not include the insulator layers 16a and 16c, the material of the insulator layer 16b is the same as the material of the insulator layers 18a and 18b, and the interlayer connection conductors v1 and v2 are via hole conductors. This is different from the transmission line 10. More specifically, the insulator layer 16b (third insulator layer) is provided below the insulator layer 18a (first insulator layer) in the vertical direction of the element body. The material of the insulator layer 16b (third insulator layer) is the same as the material of the insulator layers 18a and 18b (first insulator layer). The material of the insulator layers 16b, 18a, and 18b is a thermoplastic resin such as polyimide, liquid crystal polymer, or PTFE (polytetrafluoroethylene).

The first ground conductor layer 24 is provided on the upper main surface of the insulator layer 18a. The second ground conductor layer 26 is provided on the lower main surface of the insulator layer 18b. Interlayer connection conductors v1 and v2 electrically connect the first ground conductor layer 24 and the second ground conductor layer 26. Interlayer connection conductors v1 and v2 are via hole conductors. The via hole conductor is produced by forming through holes in the insulator layers 16b, 18a, and 18b, filling the through holes with conductive paste, and then sintering the conductive paste. The rest of the structure of the transmission line 10l is the same as the transmission line 10, so the explanation will be omitted. Furthermore, the transmission line 10l can have the same effects as the transmission line 10.

In the transmission line 10l, it is possible to reduce the transmission loss of the transmission line 10l. More specifically, in transmission lines, adhesive layers may be used to bond multiple insulator layers. However, since the adhesive layer is required to have high adhesive properties, it may be difficult to use a material having a low dielectric constant or a low dielectric loss tangent for the adhesive layer. Therefore, in the transmission line 10l, the material of the insulator layers 18a and 18b is the same thermoplastic resin as the material of the insulator layer 16b. Therefore, it becomes possible to bond the insulator layers 18a, 16b, 18b by thermocompression bonding. This eliminates the need for an adhesive layer for bonding the insulator layers. As a result, in the transmission line 10l, the transmission loss of the transmission line 10l can be reduced.

In the transmission line 10l, the material of the insulator layer 16b is the same as the material of the insulator layers 18a and 18b. Therefore, the linear expansion coefficient of the insulator layer 16b is equal to that of the insulator layers 18a and 18b. This prevents stress from occurring inside the element body 12 due to the difference between the linear expansion coefficient of the insulating layer 16b and the linear expansion coefficients of the insulating layers 18a and 18b when the temperature of the transmission line 10l changes. suppressed.

In the transmission line 10l, it is possible to form interlayer connection conductors v1 and v2, which are via hole conductors, during thermocompression bonding of the element body 12.

(13th modification)
Below, a transmission line 10m according to a thirteenth modification will be described with reference to the drawings. FIG. 22 is a cross-sectional view of the transmission line 10m.

The transmission line 10m differs from the transmission line 10l in that the interlayer connection conductors v1 and v2 are through-hole conductors. The other structure of the transmission line 10m is the same as that of the transmission line 10l, so a description thereof will be omitted. Moreover, the transmission line 10m can have the same effect as the transmission line 10l.

(14th modification)
A transmission line 10n according to a fourteenth modification will be described below with reference to the drawings. FIG. 23 is a cross-sectional view of the transmission line 10n.

The transmission line 10n differs from the transmission line 10 in that the second hole H2 is not provided. The rest of the structure of the transmission line 10n is the same as the transmission line 10, so the explanation will be omitted. Furthermore, the transmission line 10n can have the same effects as the transmission line 10. Note that the second holes H2 may not be provided in the transmission lines 10a to 10m as well.

(15th modification)
A transmission line 10o according to a fifteenth modification will be described below with reference to the drawings. FIG. 24 is a cross-sectional view of the transmission line 10o.

The transmission line 10o differs from the transmission line 10 in that it further includes signal conductor layers 22a and 22b. The signal conductor layer 22a is provided on the left side of the signal conductor layer 22 in the lateral direction of the element body. The signal conductor layer 22b is provided on the right side of the signal conductor layer 22 in the lateral direction of the element body. The rest of the structure of the transmission line 10o is the same as the transmission line 10, so the explanation will be omitted. Furthermore, the transmission line 10o can have the same effects as the transmission line 10. Note that the transmission line 10o may include two signal conductor layers, or may include four or more signal conductor layers. Furthermore, two adjacent signal conductor layers among the plurality of signal conductor layers may constitute a differential transmission line. Note that the transmission lines 10a to 10m may further include signal conductor layers 22a and 22b.

(Other embodiments)
The transmission line according to the present invention is not limited to the transmission lines 10, 10a to 10o, and can be modified within the scope of the gist. Note that the configurations of the transmission lines 10, 10a to 10o may be arbitrarily combined.

Note that in all cross sections of the transmission lines 10, 10a to 10o, the left portion S1L of the first hole forming surface S1 does not need to have a portion located to the left of the upper end P1LU and the lower end P1LD in the horizontal direction of the element body. . Therefore, in a part of the cross section of the transmission lines 10, 10a to 10o, the left portion S1L of the first hole forming surface S1 must have a portion located to the left of the upper end P1LU and the lower end P1LD in the horizontal direction of the element body. Bye.

In addition, in all the cross sections of the transmission lines 10, 10a to 10o, the right part S1R of the first hole forming surface S1 does not need to have a part located to the right of the upper end P1RU and the lower end P1RD in the horizontal direction of the element body. . Therefore, in a part of the cross section of the transmission line 10, 10a to 10o, the right portion S1R of the first hole forming surface S1 has a portion located to the right of the upper end P1RU and the lower end P1RD in the horizontal direction of the element body. Bye.

Note that the second ground conductor layer 26 is not an essential component in the transmission lines 10, 10a to 10o. Furthermore, since the transmission line 10 does not include the second ground conductor layer 26, the insulator layers 18b and 16c, and the protective layer 20b, the signal conductor layer 22 and the first ground conductor layer 24 have a microstrip line structure. It's okay.

In the transmission lines 10, 10a to 10o, the right portion S1R of the first hole forming surface S1 is a portion located to the right in the lateral direction of the element body from the upper end P1RU and the lower end P1RD in a cross section orthogonal to the longitudinal direction of the element body. It does not have to have. However, when both the left part S1L and the right part S1R are curved, the insulator layer 16a and the insulator layer 18a are The transmission loss of the transmission line 10 can be effectively reduced while effectively suppressing peeling of the insulator layer 16b and the insulator layer 18a. Note that in the transmission lines 10i and 10k, the insulator layer 18a may be an anisotropic conductive film. In this case, the plurality of conductors 200 are minute metal particles of an anisotropic conductive film.

Note that in the transmission lines 10, 10a to 10o, the signal terminals 28a and 28b may be provided on the lower main surface of the element body 12.

Note that the transmission lines 10, 10a to 10o may further include other circuits in addition to the stripline line.

Note that electronic components other than the connectors 30a and 30b may be mounted on the transmission lines 10, 10a to 10o.

Note that the transmission lines 10, 10a to 10o have a linear shape when viewed in the vertical direction of the element body. However, the transmission lines 10, 10a-10o may be curved. Here, "the transmission lines 10, 10a to 10o are curved" means that the transmission lines 10, 10a to 10o have a curved shape when no external force is applied to them.

Note that in the transmission lines 10, 10a to 10o, the first hole H1 and the second hole H2 are provided in the non-bending sections A1 and A3, and may not be provided in the bending section A2.

In the transmission line 10, the right portion S1R of the first hole-forming surface S1 may have a shape that is not bilaterally symmetrical to the left portion S1L of the first hole-forming surface S1. For example, when the distance between the signal conductor layer 22 and the lower end P1LD is different from the distance between the signal conductor layer 22 and the lower end of P1RD, the right part S1R of the first hole forming surface S1 is different from the left part of the first hole forming surface S1. It has a shape that is not bilaterally symmetrical to S1L. In such a case, it is sufficient that the one closer to the signal conductor layer 22 of the left part S1L and the right part S1R is curved. Further, it is sufficient that the one closer to the signal conductor layer 22 of the left part S1L and the right part S1R is curved more than the one farther from the signal conductor layer 22 of the right part S1R and left part S1L. However, if the curvature between the left portion S1L and the right portion S1R is too large, the transmission line 10 will be easily damaged by impact. Therefore, the width of the left portion S1L in the left-right direction or the width of the right portion S1R in the left-right direction may be smaller than the thickness of the transmission line 10 in the vertical direction.

1: Electronic equipment 10, 10a to 10o: Transmission line 12: Element bodies 16a to 16f, 18a to 18d: Insulator layers 20a, 20b: Protective layers 22, 22a, 22b: Signal conductor layer 24: First ground conductor layer 26 : Second ground conductor layer 27, 27a, 27b: Third ground conductor layer 28a, 28b: Signal terminal 30a, 30b, 102a, 102b: Connector 100, 110: Circuit board 150, 152, 160, 162: Conductor layer 200: Conductor 500: Transmission lines A1, A3: Non-bending section A2: Bending section H1, H11, H21, H31: First hole H2, H12, H22, H41: Second hole H3, H4, H13, H14, H23 , H24: Holes P1LU, P1RU, P2LU, P2RU: Upper end P1LD, P1RD, P2LD, P2RD: Lower end S1: First hole formation surface S1L, S2L: Left part S1R, S2R: Right part S2: Second hole formation Surfaces h1 to h6: Openings v1 to v4: Interlayer connection conductors

Claims (3)

an element body having a main surface having a normal extending in the vertical direction of the element body, the element body including a single layer of a first insulator layer and a second insulator layer;
a signal conductor layer provided in the element body below the first insulator layer in the element body vertical direction;
a first ground conductor layer provided above the first insulator layer in the element body in the vertical direction of the element body;
It is equipped with
The first insulator layer is provided with a first hole that penetrates the first insulator layer in the vertical direction of the element body,
The second insulator layer is provided with a second hole that penetrates the second insulator layer in the vertical direction of the element body,
The direction in which the signal conductor layer extends is defined as the front-back direction of the element body,
The line width direction of the signal conductor layer is defined as the element body left and right direction,
At least a portion of the first hole overlaps with the signal conductor layer when viewed in the vertical direction of the element body,
A surface of the first insulating layer forming the first pores is defined as a first pore formation surface,
A surface on which the second insulating layer forms the second pores is defined as a second pore formation surface,
The left portion of the first pore-forming surface has a portion located to the left of the second pore-forming surface in the lateral direction of the element in a cross section perpendicular to the longitudinal direction of the element.
transmission line. the first insulator layer is thinner than the second insulator layer;
The transmission line according to claim 1. the first insulator layer is an adhesive layer;
The transmission line according to claim 1 or claim 2.

Images